This invention relates to a spinning device for open end spinning machines, and more particularly to dirt removal in the spinning device.
As is well known in the art, there is a spinning device for an open end spinning machine of the type comprising a rotary spinning chamber, feeding and combing means for feeding a supplied sliver into the rotary spinning chamber, and a discharge channel through which the finished yarn is withdrawn. The feeding and combing means includes a combing roller to which the sliver is fed and combed out into individual fibers. By the combing roller, the individual fibers are fed to a removal position thereof and hence into the rotating spinning chamber. On the way of the individual fibers to the removal position, there is a dirt discharging opening through which dirt contained in the sliver, such as pusks, neps or short fibers having a length shorter than the width of the dirt discharge opening, is thrown out by centrifugal force toward a dirt collecting chamber. The dirt collecting chamber is provided with an air inlet and outlet to produce an air current flowing therethrough, thereby continuously removing the dirt particles out of the dirt collecting chamber. In order to prevent the fibers from passing out through the dirt discharge opening, that is to carry out an efficient separation of the dirt from the fibers, there is a dirt separating channel through which an air current is introduced into the fibers at a position near the dirt discharge opening.
In such a conventional spinning device, a part of the air current flowing through the air inlet into the outlet tends to flow into the fibers along with the air current passing through the dirt separating channel, whereby the dirt particles once contained in the dirt collecting chamber are moved back toward the dirt discharge opening. This unfavourably affects the separation of the dirt from the fibers, resulting in a poor cleanliness of the finished yarn.
One of possible methods for eliminating this disadvantage is to decrease a velocity of the air current flowing through the air inlet and outlet provided in the dirt collecting chamber. However, the decreased velocity of the air current is accompanied by a poor removal of the dirt particles contained in the dirt collecting chamber and therefore this method can not be brought into practice.